I can't comment on the energy efficiency although it should be better than the halogen bulbs I replaced and I don't know about the durability as I haven't had them long. However, brightness is just what I need for overhead lighting in my kitchen. The color is bluer than halogens, but we don't find it excessive or annoying. We had no issues with them flickering when power was reduced. They were advertised with glass lids. You are not. This can be a problem when placed in the oven hood. So far they're an improvement and I'm glad we got them. Now I need to find tiny LEDs to fit in my counter lighting.